Question Time, metropolitanism and the vagaries of tri-party debate

During last week's Question Time, David Dimbleby warned the speakers that they were getting a little bit stuck in the intricacies of London politics, which was perhaps unsurprising because the panel consisted of the three main candidates running to become Mayor of London today. We can presumably look forward to the Gardener's Question Time chair pleading with speakers to stop banging on about hollyhocks.

But the exchange was revealing of a tension in broadcasting about coverage of London issues in a TV culture in which almost all the production takes place in the capital, yet there is a terror of being accused of "metropolitanism", notes Mark Lawson.

The mayoral race is strictly a local story but, unusually, the 2008 contenders all have significant national profiles. So Question Time aimed for a sort of soap-opera show: a clash of personalities, with Dimbleby stepping quickly in if anyone mentioned congestion in the Blackwall Tunnel.

Yet, while the showdown of show-offs was entertaining, another consequence of this Question Time, I suspect, will be to increase the odds against a televised debate between the prime ministerial candidates; the long dream of British broadcasters. The problem, as the Ken-Boris-Brian punch-up confirmed, is that political fisticuffs of this kind are unsuited to a three-party system because two candidates will tend to gang up on the other one. This happened most famously in the 1992 US race, when Ross Perot helped to make Bill Clinton president by alternating punches against the first President Bush.

American elections usually have two candidates and so the classic one-on-one stand-off works. In Britain, though, a trio of leaders is the default and so what happened last week - with Paddick helping Livingstone to duff up Johnson - would occur in any PM threesome, making it unwise for the Labour or Tory contender to take the risk. But at least there'd be no risk of them being warned not to get bogged down in "national" issues.